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CoxOrb RAPIDFIT Coaching and Data Oarlock


Available Early 2020!

RAPIDFIT Coaching and Data Oarlock

RapidFit Coaching and Data Oarlocks (Patent Pending) are a complete solution to the historical problem of how to make telemetry usable in rowing on a day to day basis.

• Install in under a minute

• Can be used either as a coaching aid, or to gather performance data, or both

• Allows easy adjustment of Height and Pitch

• 2% accuracy on power and 0.5 degrees on angles

How they work

Rowing telemetry solutions have existed for many years, but they have always had the problem of being very time consuming to install. They have only really been usable when they can either be left on a single boat or the programme has a professional boatman. Even the latest designs take ten minutes to move between boats so an Eight takes almost an hour and a half to set up and this makes them impractical in most situations.
The RapidFit Oarlocks are a two part design: a low cost moulded oarlock that replaces the ones on your boats, and a sensing module that can then be fitted in under a minute.
We have also developed a method of increasing the accuracy, and speeding up, setting the zero datum of each oarlock on initial installation.

Sensing Module

The sensing module measures forces perpendicular to the oarlock face, which means that outward applied pressure has no impact. Not doing this is a significant drawback of at least one competitor. The design of the RapidFit Oarlock also means that re-zeroing the strain gauges to allow for temperature changes, etc., is done automatically each stroke during the recovery as the weight of the oar is not seen by the force sensor.



Each oarlock incorporates an RFID chip, like those used to identify animals, and when a sensing module is fitted it picks up key data from the chip:

• The standard Span for the boat

• The standard overall and inboard oar lengths for the boat

• The trigger force for slip angle measurements

• Set up information so that the module can determine the angular zero datum

All the rigging data can then be changed using the paired ActiveSpeed if the rig has been significantly altered from the standard set up for that boat.

Zero Datum Sensing

A mirror strip on a sleeve on the pin is picked up by the infrared emitter/receiver in the sensing module each stroke. This sets the zero datum for that stroke so that the inherent drift of MEMS Gyro sensors does not cause a problem. The length of the strip means that the oarlock can be moved up and down using standard clips.


Blanking Module

When the sensing module is not fitted a simple moulded blanking module replaces it.

Initial Installation

When the oarlocks are first installed you can set their zero datums in the conventional way by laying a straight edge across the boat. However this can be time consuming, and can also be hard to do accurately, so we have developed an approach using a low cost laser device and a bespoke laser target. The target is clipped to an adjacent oarlock in sweep boats, or the one opposite in sculling boats, and you then target the laser onto the target while holding the laser’s base against the oarlock’s face.


Operation Modes

RapidFit Oarlocks work with our ActiveSpeed units to both display data and share it with coaches, using the ActiveSpeed’s built in radio link.

There are three main ways to use them:

1. To display force curves

Force curves can be displayed one stroke at a time or averaged over 2-10 strokes. They can also be overlaid onto an ‘ideal’ force curve, selected from a range of options, or a modified version of one of those options. They can either be shown weight compensated or unmodified and be set to fill the display vertically or be displayed to scale. In addition, up to two numerical values can be displayed at the same time e.g.: power, catch slip angle, etc.

2. To show coaching information in two, four or six fields

• Total Stroke Angle

• Catch Angle

• Finish Angle

• Effective Stroke Angle

• Catch Slip

• Finish Slip

• Ratio between power phase and recovery

You can also display standard parameters, such as stroke rate and distance, with any of these.

3. To show Power related data, or a combination of these and coaching information

• Power (averaged over 1-10 strokes)

• Average Power (since timer started)

• Work per stoke (averaged over 1-10 strokes)

• Average Work per stroke (since timer started)

• Peak Force (averaged over 1-10 strokes)

• Peak Force Angle (averaged over 1-10 strokes)

• Average Force over stroke (averaged over 1-10 strokes)

Again, you can also display standard parameters, such as stroke rate and distance, with any of these.


Data can be quickly and easily transferred from the ActiveSpeed to our DataFlow app which allows easy and automatic transfer to RoweRS, Rowsandall, Training Peaks, Strava, Golden Cheetah, etc. All performance data, including power related output, is transfered, but force curves and angle data can’t currently be viewed and analysed on these sites so you need to use the DataFlow app for that.


Further information on the background of the Oarlock can be found below.




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